In an electrostatic energy harvester which harvests energy using an electrostatic phenomenon generated by friction, the energy is generated due to a charge difference caused by electrostatic charges generated when two materials are in non-contact with each other after being in contact with each other.
The electrostatic energy harvester is referred to as an eco-friendly energy harvester having a new concept in which electricity energy can be infinitely extracted from consumable mechanical energy generated by fine vibration or movement of humans which exist everywhere, in contrast with conventional eco-friendly energy such as solar batteries, wind power, fuel cells, etc. An energy conversion method using the electrostatic property has high conversion efficiency, can be used for producing small and light products, and has been evaluated as new technology leading to a breakthrough technology leap and having great ripple effects through fusion of the energy conversion method and nanotechnology.
In conventional electrostatic energy harvesters, output of a device is generally determined based on a selection of a material depending on triboelectric series. Thus, research is mostly focused on a control of a device structure or a surface shape of the material rather than the selection of the material.
To overcome the above, the invention disclosed in Korea Patent Registration No. 10-1398708, which controls an electrostatic property generated by friction using electrical potentials generated by a ferroelectric property of a material, amplifies a charge difference of the material caused by the friction to constantly maintain the output of an electrostatic energy harvester, and thus the output thereof can be significantly improved, is suggested. The above invention is a patent made by the research staff of the present invention, and the output is improved by a selection of a material. However, a ferroelectric material is in direct contact with a frictional charged material, and a problem in that frictional heat damages the ferroelectric material occurs when the ferroelectric material is repeatedly in contact with the frictional charged material.